US 11,748,145 B2
Data processing system using skeleton virtual volumes for improved system startup
Vasu Subramanian, Chapel Hill, NC (US); and Yakov Stanislavovich Belikov, Saint Petersburg (RU)
Assigned to EMC IP Holding Company LLC, Hopkinton, MA (US)
Filed by EMC IP Holding Company LLC, Hopkinton, MA (US)
Filed on Jan. 15, 2021, as Appl. No. 17/150,041.
Prior Publication US 2022/0229680 A1, Jul. 21, 2022
Int. Cl. G06F 9/455 (2018.01)
CPC G06F 9/45558 (2013.01) [G06F 9/45541 (2013.01); G06F 2009/45579 (2013.01); G06F 2009/45583 (2013.01)] 23 Claims
OG exemplary drawing
 
1. A method of operating a computer system having a VM host computer coupled to a separate data storage system, the VM host computer hosting a virtual machine (VM), the data storage system providing physical storage resources and related mapping logic to store a VM-owned virtual volume (vVol) on the data storage system on behalf of the VM, the method comprising:
during a first operating session of a virtual machine (VM), storing persistent metadata and first-session working data of the VM on a VM-owned virtual volume (vVol), the working data being session specific and not persisting across operating sessions, the persistent metadata describing aspects of the vVol and persisting across operating sessions, the persistent metadata identifying a variable allocated size of the vVol that varies during the first operating session according to a size of the first-session working data;
at the end of the first operating session, performing unmap operations to deallocate underlying physical storage for the working data of the vVol, and transitioning the vVol to a skeleton condition vVol storing only the persistent metadata identifying reduced allocated size accordingly; and
at the beginning of a subsequent second operating session of the VM, and based on the existence of the vVol as the skeleton vVol, resuming use of the vVol for storing the persistent metadata and second-session working data of the VM during the second operating session, including using the persistent metadata to reflect growth of the vVol to accommodate the second-session working data.